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The purpose of this section of CEACCP is to provide a forumfor debate and clarification of any controversies arising fromprevious articles This month we received correspondence from Drs Andy Petros,Richard Sarginson, Mark Fox and Rick van Saene of London andLiverpool commenting on the article by Ken Inweregbu, JayshreeDave and Alison Pittard on ‘Nosocomial infections’(CEACCP 2005; 5: 14–17). Dr Petros and colleagues stated     

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The purpose of this section of CEACCP is to provide a forumfor debate and clarification of any controversies arising fromprevious articles. We have received correspondence from Bruce Powell of FremantleHospital, Western Australia in connection with the article ‘Currentcontroversies in neuroanaesthesia, head injury management andneuro critical care’ by Drs Mishra, Rajkumar and Hancock(CEACCP 2006; 6,2:79–82). Dr Powell questions the suggestionthat ‘blood glucose should be strictly maintained at     

Desflurane compared with propofol for postoperative sedation in the intensive care unit

Background. We hypothesized that emergence from sedation inpostoperative patients in the intensive care unit would be fasterand more predictable after sedation with desflurane than withpropofol. Methods. Sixty patients after major operations were allocatedrandomly to receive either desflurane or propofol. The targetlevel of sedation was defined by a bispectral index^TM (BIS^TM)of 60. All patients were receiving mechanical ventilation ofthe lungs for 10.6 (SD 5.5) h depending on their clinical state.The study drugs were stopped abruptly in a calm atmosphere withthe fresh gas flow set to 6 litres min^–1, and the timeuntil the BIS increased above 75 was measured (t_BIS75, the mainobjective measure). After extubation of the trachea, when thepatients could state their birth date, they were asked to memorizefive words. Results. Emergence times were shorter (P<0.001) after desfluranethan after propofol (25th, 50th and 75th percentiles): t_BIS75,3.0, 4.5 and 5.8 vs 5.2, 7.7 and 10.3 min; time to first response,3.7, 5.0 and 5.7 vs 6.9, 8.6 and 10.7 min; time to eyes open,4.7, 5.7 and 8.0 vs 7.3, 10.5 and 20.8 min; time to squeezehand, 5.1, 6.5 and 10.2 vs 9.2, 11.1 and 21.1 min; time to trachealextubation, 5.8, 7.7 and 10.0 vs 9.7, 13.5 and 18.9 min; timeto saying their birth date, 7.7, 10.5 and 15.5 vs 13.0, 19.4and 31.8 min. Patients who received desflurane recalled significantlymore of the five words. We did not observe major side-effectsand there were no haemodynamic or laboratory changes exceptfor a more marked increase in systolic blood pressure afterstopping desflurane. Using a low fresh gas flow (air/oxygen1 litre min^–1), pure drug costs were lower for desfluranethan for propofol (95 vs 171 Euros day^–1). Conclusions. We found shorter and more predictable emergencetimes and quicker mental recovery after short-term postoperativesedation with desflurane compared with propofol. Desfluraneallows precise timing of extubation, shortening the time duringwhich the patient needs very close attention. Br J Anaesth 2003; 90: 273–80     

Errata

Prediction of depth of sedation and anaesthesia by     

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The purpose of this section of CEACCP is to provide a forumfor debate and clarification of any controversies arising fromprevious articles Dr Christian Egeler of Morriston Hospital, Swansea, wrote inconnection with the article by Phil Dalrymple and Subbiah Chelliahon electrical nerve locators (CEACCP 2006; 6,1: 32–6)to suggest another mechanism to explain the disappearance ofthe elicited muscular     

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92373 Model to describe the degree     

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Severe meningococcal disease in childhood (BJA 2003;      

Symptom clusters in incident dialysis patients: associations with clinical variables and quality of life

Background. To date, the pathophysiology underlying symptomsin renal patients is still unclear. Symptom management researchsuggests that identification of related clusters of symptomscould provide insight into underlying determinants associatedwith multiple symptom experience. Theoretically, symptoms withina cluster could have a synergistic relationship. We aimed toidentify symptom clusters in incident dialysis patients, andinvestigated associations between symptom clusters, clinicalvariables, functional status as measured by the Karnofsky Indexand quality of life. Methods. 1553 haemodialysis (HD) and peritoneal dialysis (PD)patients completed the Kidney Disease Quality of Life ShortForm symptom/problem list at 3 months after the start of dialysis.Principal component analysis using varimax rotation was usedto identify symptom clusters. Results. Patients were bothered by an average of 2.8 (±2.4)symptoms of ‘moderate bother’ or more. Three clusterswere identified, explaining 49% of the total variance. All clustersshowed strong negative associations with the SF-36 quality oflife dimensions (–0.142 to –0.593) and with functionalstatus (–0.130 to –0.332) in HD and PD patients.In contrast, only the clinical variables serum albumin (–0.084to –0.232) and haemoglobin (–0.068 to –0.126)were associated with all clusters in HD patients, and Kt/V_urea(–0.089 to –0.125) in PD patients. Conclusions. Symptom clustering does not explain the lack ofmeaningful associations between symptoms and clinical variables.Strong associations of symptom clusters with quality of lifedimensions suggest that psychological factors could better explainsymptom burden. Patients’ perceptions of symptoms shouldbe routinely assessed as part of clinical care to improve self-managementstrategies.     

Errata

90304 Comparison of ropivacaine 0.5% (in glucose 5%)     

Effect of diclofenac on cerebral blood flow velocity in patients with supratentorial tumours

Background. The aim of this investigation was to determine theeffects of diclofenac on cerebral blood flow. Middle cerebralartery blood flow velocity was measured in nine patients withsupratentorial tumours. Methods. Using a transcranial Doppler ultrasound, we measuredthe baseline mean and systolic cerebral blood flow velocity.Measurements were repeated following administration of diclofenac75 mg i.v. Results. There was no significant change in cerebral blood flowvelocity. All other physiological variables remained constant. Conclusion. Diclofenac does not cause a significant change incerebral blood flow velocity in patients with supratentorialtumours. Br J Anaesth 2002; 89: 762–4     

Effects of xenon on acetylcholine release in the rat cerebral cortex in vivo

Background. We have reported previously the effects of severalanaesthetics on cholinergic activity in the central nervoussystem (CNS). In this study, we report the effects of xenonon cholinergic cell activity. Methods. Using in vivo brain microdialysis, we measured acetylcholine(ACh) release in the rat cerebral cortex in vivo during xenonanaesthesia. Results. Xenon induced an initial increase in ACh release, followedby a gradual decrease. The level of Ach release at 40 min ofxenon administration was significantly higher than the control. Conclusions. Xenon activates CNS cholinergic cell activity followedby development of acute tolerance. Br J Anaesth 2002; 88: 866–8     

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Gordon Drummond of Edinburgh contacted us regarding the articleon ‘Pharmacokinetics and Anaesthesia’ by Fred Robertsand Dan Freshwater-Turner (CEACCP 2007; 7(1): 25–29).He was unhappy with the assertion that ‘an inhaled drug...crossesthe alveolar membrane into the blood along its partial pressuregradient. This produces an exponential wash-in...’. DrDrummond writes that ‘This suggests that the exponentialwash-in is caused by a partial pressure gradient. This is notso. Volatile anaesthetics are believed by almost all to equilibraterapidly and virtually fully, between alveolar gas and alveolarcapillary blood, and     

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We received correspondence from Nick Lavies of Worthing in connectionwith the article by Radha Ravi and Tanya Howell on ‘Anaesthesiafor paediatric ear nose and throat surgery’ (CEACCP 2007;7(2): 33–37). Dr Lavies commented on the issues of airwaymanagement, management of the bleeding tonsil, and anaesthesiafor oesophagoscopy. He questioned the statement that ‘only16% of anaesthetists used the reinforced laryngeal mask airwayroutinely. However, no mention is made of the CJD problem whichforced me and I suspect a good     

Comparison of measured and estimated angles of table tilt at Caesarean section

Background. Lateral maternal tilt reduces aortocaval compressionand the consequent cardiovascular instability. Methods. We measured the angle of table tilt used by 16 anaesthetistsduring uncomplicated, elective Caesarean section. After initiatinganaesthesia, they were asked to position the patient and estimatethe angle of tilt, which was then measured. Results. Almost every anaesthetist positioned the patient lessthan 15° because they overestimated the angle of tilt. Whenquestioned on their knowledge of the current advice for lateraltilt, 11 of the 16 anaesthetists were aware of the 15° recommendation. Conclusion. Estimation of the angle of table tilt is unreliable. Br J Anaesth 2003; 90: 86–7     

Posture used by anaesthetists during laryngoscopy

Background. There is little advice on the posture to be usedwhen intubating the trachea. Does the stance used depend onexperience? Methods. Twenty-six subjects with varying experience of intubationwere photographed during laryngoscopy of an intubation trainingmannequin. Posture was measured from the photographs and thedata were analysed with the Mann–Whitney U-test. Results. The less experienced group had shallower lines of sight,levered more, and stood with their face closer to the mannequin(P=0.037, 0.018 and 0.06 respectively). Conclusions. Novice anaesthetists should be given explicit instructionson correct trolley height and should be taught to intubate witha straight back. Br J Anaesth 2002; 89: 772–4     

Bacterial contamination of epidural needles after multiple skin passes

Background. Infection and epidural abscess are important complicationsof epidural analgesia. Difficult insertion may be associatedwith an increased risk of bacterial contamination of the epiduralneedle or catheter. Methods. Bacterial contamination of epidural needles and trocarsafter difficult epidural insertion, defined as two or more skinpasses, was assessed in 38 obstetric and ten gynaecologicalpatients. Results. There was no bacterial growth on any of the 48 epiduralneedles or trocars despite the mean (range) insertion time being20 (10–30) min and the number of insertion attempts being3 (2–4). Conclusions. Difficult epidural insertion is not associatedwith an increased risk of needle contamination and is thereforean unlikely source of epidural infection. Br J Anaesth 2002; 89: 922–4     

Unintentional arterial puncture during cephalic vein cannulation: case report and anatomical study

Background. The cephalic antebrachial vein is often used forvenous access. However, superficial radial arteries of the forearmare known and unintentional arterial puncture can result fromattempts to cannulate the lateral veins of the arm. Methods. Accidental puncture of a superficial radial arteryduring peripheral venous cannulation prompted us to study theanatomy of 26 specimens and to assess the relationship betweenthe radial artery and the cephalic vein in the forearm. Results. In two cases, we found accessory branches of the radialartery close to the cephalic forearm vein. Venous cannulationat the lateral wrist carries a small risk of arterial punctureif arterial anomalies are present. Conclusions. If venous cannulation is attempted at the radialside of the wrist, palpation for pulsation should reduce thedanger of arterial puncture. Br J Anaesth 2004: 92: 740–2     

Fibreoptic tracheal intubation after placement of the laryngeal tube

Background. The laryngeal tube is a new alternative for securingthe airway. After adequate oxygenation, insertion of a trachealtube is still required in many situations. In such circumstances,fibreoptic placement of a tube exchange catheter after placementof the laryngeal tube is possible before tracheal intubation.Throughout the procedure, oxygen administration can continuevia the laryngeal tube, the tube exchange catheter and the trachealtube. Methods. The feasibility of this technique was tested in 10patients scheduled for elective surgery. Results. The laryngeal tube was placed at the first attemptwith adequate ventilation in all patients. The tube exchangemanoeuvre was performed successfully in all but one patient. Conclusion. This technique is an important alternative for airwaymanagement and provides a significant degree of patient safety. Br J Anaesth 2002; 89: 733–8     

A Scottish National Prospective Study of airway management skills in new-start SHOs

Background. There is increasing concern about the ability ofjunior anaesthetists to manage the airway correctly and alarmthat this may lead to adverse events. Methods. We monitored the airway management skills of new-startanaesthetists in Scotland for 3 months. Results. Experience with the laryngeal mask airway was satisfactorybut there was wide variation in numbers of facemask and trachealintubation cases. Conclusions. We recommend that facemask anaesthesia is givena high priority in the formative months and that a target numberof intubations should be carried out before providing anaesthesiawithout direct supervision.      

Predictive performance of computer-controlled infusion of remifentanil during propofol/remifentanil anaesthesia

Background. The predictive performance of the available pharmacokineticparameter sets for remifentanil, when used for target-controlledinfusion (TCI) during total i.v. anaesthesia, has not been determinedin a clinical setting. We studied the predictive performanceof five parameter sets of remifentanil when used for TCI ofremifentanil during propofol anaesthesia in surgical patients. Methods. Remifentanil concentration–time data that hadbeen collected during a previous pharmacodynamic interactionstudy in 30 female patients (ASA physical status I, aged 20–65 yr)who received a TCI of remifentanil and propofol during lowerabdominal surgery were used in this evaluation. The remifentanilconcentrations predicted by the five parameter sets were calculatedon the basis of the TCI device record of the infusion rate–timeprofile that had actually been administered to each individual.The individual and pooled bias [median performance error (MDPE)],inaccuracy [median absolute performance error (MDAPE)], divergenceand wobble of the remifentanil TCI device were determined fromthe pooled and intrasubject performance errors. Results. A total of 444 remifentanil blood samples were analysed.Blood propofol and remifentanil concentrations ranged from 0.5to 11 µg ml^–1 and 0.1 to 19.6 ng ml^–1respectively. Pooled MDPE and MDAPE of the remifentanil TCIdevice were –15 and 20% for the parameter set of Mintoand colleagues (Anesthesiology 1997; 86: 10–23), 1 and21%, –6 and 21%, and –6 and 19% for the three parametersets described by Egan and colleagues (Anesthesiology 1996;84: 821–33, Anesthesiology 1993; 79: 881–92, Anesthesiology1998; 89: 562–73), and –24 and 30% for the parameterset described by Drover and Lemmens (Anesthesiology 1998; 89:869–77). Conclusions. Remifentanil can be administered by TCI with acceptablebias and inaccuracy. The three pharmacokinetic parameter setsdescribed by Egan and colleagues resulted in the least biasand best accuracy. Br J Anaesth 2003; 90: 132–41